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    Estimating Concrete and Rebar PDF

    Uploaded by

    allen2912
    This document provides information and methods for estimating concrete and rebar quantities for foundations. It discusses three methods for concrete takeoffs: building line, center line, and sectioning. The centerline method is most common, avoiding counting corners twice. A quick estimating tip is given to calculate concrete volumes in footings by multiplying the cross-sectional area by 0.000257. Formwork is measured in square feet of contact area. Labor for placing concrete is about 50-70 cubic yards per 8-hour day. The objectives are correctly setting up an estimate, calculating perimeter, setting up foundation takeoff, and calculating costs.

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    Estimating Concrete and Rebar PDF

    Uploaded by

    allen2912
    323 views8 pages
    This document provides information and methods for estimating concrete and rebar quantities for foundations. It discusses three methods for concrete takeoffs: building line, center line, and sectioning. The centerline method is most common, avoiding counting corners twice. A quick estimating tip is given to calculate concrete volumes in footings by multiplying the cross-sectional area by 0.000257. Formwork is measured in square feet of contact area. Labor for placing concrete is about 50-70 cubic yards per 8-hour day. The objectives are correctly setting up an estimate, calculating perimeter, setting up foundation takeoff, and calculating costs.

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    Original Title

    Estimating-Concrete-and-Rebar.pdf

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    This document provides information and methods for estimating concrete and rebar quantities for foundations. It discusses three methods for concrete takeoffs: building line, center line, and sectioning. The centerline method is most common, avoiding counting corners twice. A quick estimating tip is given to calculate concrete volumes in footings by multiplying the cross-sectional area by 0.000257. Formwork is measured in square feet of contact area. Labor for placing concrete is about 50-70 cubic yards per 8-hour day. The objectives are correctly setting up an estimate, calculating perimeter, setting up foundation takeoff, and calculating costs.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    323 views8 pages

    Estimating Concrete and Rebar PDF

    Uploaded by

    allen2912
    This document provides information and methods for estimating concrete and rebar quantities for foundations. It discusses three methods for concrete takeoffs: building line, center line, and sectioning. The centerline method is most common, avoiding counting corners twice. A quick estimating tip is given to calculate concrete volumes in footings by multiplying the cross-sectional area by 0.000257. Formwork is measured in square feet of contact area. Labor for placing concrete is about 50-70 cubic yards per 8-hour day. The objectives are correctly setting up an estimate, calculating perimeter, setting up foundation takeoff, and calculating costs.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 8
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    The key takeaways from the document are the different methods for estimating concrete foundations, including building line, sectioning, and centerline length estimates. It also discusses calculating rebar and formwork requirements as well as how to estimate labor costs.

    The three methods for estimating concrete discussed are the building line method, sectioning method, and centerline length method.

    The formula given for calculating the centerline length is: Outside Building line length or perimeter – (4 * thickness or width of any given strip)

    Estimating Concrete and

    Rebar

    Course objectives
    • Correctly setting up an estimate
    • Calculating the perimeter
    • Setting up the concrete foundation takeoff
    • Calculating concrete labor and material
    costs

    Concrete takeoff for foundations


    • 3 methods to use
    – building line
    – center line
    – sectioning

    Provide HO #1

    1
    Building line estimates
    • Used for small projects (residential)
    • fast, easy

    • problem – counts corners twice

    Add perimeter (48 + 48 + 26 +26) = 148.0 ft. or 2(L + W)


    148.0 ft x 8.0 ft x 0.83 ft = 982.72 cf.

    Sectioning
    • Breaks construction down into smaller
    pieces

    • More accurate
    • More time consuming

    • Use where large volumes of concrete


    required, but unusual angles, etc.

    2
    Sectioning – red 2) 24.33 ft x 8.0 ft x 0.83 ft = 323.10 cf.
    blue 2) 48.0 ft x 8.0 ft x 0.83 ft = 637.44 cf. sum = 960.54 cf

    Centerline length
    • Avoids adding corners twice
    • Most common method in commercial wk
    – Useful for conc., rebar, walls, etc.
    • Formula to know:
    “Outside Building line length or perimeter – (4
    * thickness or width of any given strip)”
    SOL = Po – (4T)

    Complete in-class activity #1


    calculate the amount of footing
    concrete required

    distance from centerline of the


    construction line to the building line

    = 10 inches (0.83 inches)

    3
    Centerline length method
    • Building line length = (perimeter) = 148.0 ft
    • Distance from centerline to bldg. line =
    • 148.0 ft – (4*.83) = 144.67 (true perimeter)

    • 144.67 ft * 8 ft * 0.83ft = 960.59 cf.

    Centerline length caveat


    • Only works if all walls and offsets are 90°

    Quick estimating tip


    • Short cut for estimating concrete in any
    footing

    • Multiply the cross-section in square inches


    by 0.000257. Gives CY/lineal ft

    • Multiply that result by number of lineal feet


    in the footing

    4
    Quick estimating tip illustrated
    • Given: A footing 7-in deep and 22-in wide
    is 160-ft long.
    Calculate the yards of concrete reqd.

    (7" * 22")*160' * .000257 = 6.33 CY

    DO NOT Convert inches to decimals except when


    part of next foot (e.g., 38’-7”)

    Estimating footings (pads)

    Estimating footings (pads)


    • List the description or title from schedule
    Provide HO#2

    5
    Calculating Rebar
    • Rebar – weight per
    linear foot

    • See text (pg. 133 for


    splicing req.

    Calculating formwork
    • 2 Types
    – Structural (concrete) formwork
    • Foundations
    • Walls
    • Columns
    • Beams
    – Flatwork (flat concrete work)
    • Sidewalks
    • Driveways
    • Slabs

    Structural (concrete) formwork


    • Formwork – measured in SFCA

    6
    Measuring concrete walls
    • Use centerline
    length * height
    *2

    Refer to HO#1
    Calculate the formwork
    and concrete required for
    the wall

    Labor placing concrete in


    foundations
    • 50- 70 CY/8 hr day
    (direct from truck to
    footing)

    How is labor calculated?

    Quantity of Work
    Duration =
    Rate of Production

    Using HO #1 calculate the duration of the footing


    installation
    (0.35 labor hours/CY – use a price of 35$/hour/man

    7
    Course objectives
    • Correctly setting up an estimate
    • Calculating the perimeter
    • Setting up the concrete foundation takeoff
    • Calculating concrete labor and material
    costs

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